<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
  </head>
  <body>
    <div id="root">
      姓：<input type="text" v-model="firstName" /><br />
      名：<input type="text" v-model="lastName" /><br />
      全名：<span>{{fullName}}</span>
    </div>
    <script>
      const vm = new Vue({
        el: "#root",
        data: {
          firstName: "张",
          lastName: "三",
        },
        computed: {
          //   fullName: {
          //     // get的作用？当有人读取fulName时，get会被调用，返回值作为fullName的值
          //     get() {
          //       return this.firstName + '-' + this.lastName;
          //     },
          //     set(value) {
          //         const arr = value.split('-');
          //         this.firstName = arr[0]
          //         this.lastName = arr[1]
          //     }
          //   },
          // },
          fullName: function () {
            return this.firstName + "-" + this.lastName;
          },
        },
      });
    </script>
  </body>
</html>
